This guide covers split load vs dual RCD vs RCBO board configurations, circuit arrangement and allocation, BS 7671 labelling requirements, type testing under BS EN 61439, SPD installation, wiring best practice, and the common mistakes found during EICR inspections. What Is a Distribution Box? A distribution box — also called a distribution board, panel board, or breaker panel — is the central electrical supply hub of any building or facility. It divides incoming power into subsidiary circuits and provides a protective fuse or circuit breaker for each one. The. The International Electrotechnical Commission (IEC) provides globally recognized standards including IEC 61439 series that specifically address low-voltage switchgear and controlgear assemblies. Procedure: UV Test according to. Our flexible distribution boxes enable reliable, decentralized signal transmission and power transmission up to protection class IP67 – wherever passive distribution boxes are required.